Welding system



March 10, 1953 J. F. RANDALL ETAL 2,631,215

WELDING SYSTEM Filed Aug. 24, 195o z-sHEETs-SHEET 1 JFRA/VD C? g/NTO lBy @java @v/Za/ ATTORNEYS SSSSSSSSSSS EM BY ATTORNEYS Patented Mar. 10,1953 WELDING SYSTEM John F. Randall, Detroit, and Richard E. Brooks,

Dearborn, Mich., assignors to Ford Motor Company, Dearborn, Mich., acorporation of Dela- Application August 24, 1950, Serial No. 181,278

i claim. (C1. 21a-1859 .it is "desired to weld together the edges ofthin,

mild steel'body` stock and'then grind the weld so that afterfnishing'and painting the weld will not show. This is'accomplished by securingthe two "parts to`be"welded together rigidly in a iixture with the'edges to be joined closely adjacent each other. It is diicult to securesatisfactory welds if the space between the edges of the part to bewelded exceeds one sixteenth of an inch. The portions of this fixtureadjacent the arc must be fabricated of copper or other highly conductivemetal to avoid accidental welding of the work to the iixture. The use ofhighly conductive metal in this fixture is also advantageous in that itminimizes danger of damage to the fixture from accidental contact withthe welding arc and also serves to cool the parts being welded andprevent distortion.

It is essential that the parts to be welded be secured in the die by apressure of about eight hundred pounds per lineal inch to avoid theedges of the parts being drawn together by the shrinkage of the weldmetal as the weld progresses. It is also necessary that the fixtureexactly accommodate the parts to be welded. Otherwise some parts of theedges are certain to be misaligned and result in poor welds. Thisrequires that the fixtures be made with practically the same exactitudeas metal forming dies. Even more important conventional i-eliarc weldingdies must be accorded continuous and careful maintenance to maintaintheir original precision, if defective welds are to be avoided.

In an endeavor to lower the costs of these welding xtures and expeditetheir construction, the instant invention has been developed. Thisinvention is probably best understood by a study of the figures of thedrawing in which:

Figure 1 is a diagrammatic cross section of one form of welding fixture.

Figure 2 is a diagrammatic section of a variation of the structure shownin Figure 1.

Figure 3 is a diagrammatic section of a weld- 2 Y ing apparatus with aseparate cooling means;A

Figure 4 is a diagrammatic section of a welding apparatus with anotherform of cooling. In Figure 1 the two sheet steel parts to be weldedtogether are designated by the numeral l0. These parts are showndirectly below die II which is'provided with groove I2 in alignment withthe joint to be formed between the two parts It. rlhis groove I2 isprovided for the accommodation of the welding torch. The two sheet metalparts I0 are positioned by die il and supported from below by movablemember I3, elastomer block I4, asbestos sheet' I5, and laminations I S.a"

Figure 2.is similar to Figure 1 except that elastomer block I4 isprovided with a central cavity 'I'I for the reception of hydraulic uid..

To make a weldthe movable member .I3x'is retracted sufficiently topermit the insertion of sheet metal parts I0. Movable member I3 is thenmoved towards die II sufficiently to iirmly clamp metal parts I0 betweendie II and laminations I B. The welding operation is now performed andmovable member I3 is retracted sufiiciently to permit the welded piecesto be removed from the die. The operation of the apparatus shown inFigure 2 is similar to that of Figure l except that the introduction ofhydraulic fluid under pressure into central cavity I1 is substitutedwholly or in part for movement of movable member i3.

Laminations i6 are preferably made of copper although any availablemetal having a high thermal conductivity may be employed.

The prime purpose of these laminations is to provide a support for thepieces to be welded which is sumciently flexible and yielding to enableit to conform to irregularities and inaccuracies in the fixture andpieces to be welded and still exert a sufficiently intense clampingpressure. Another purpose of these laminations is to prevent the flow ofheat from the weld to the elastomer. This is accomplished because thehigh thermal conductivity of the laminations tends to transmit the heatin a plane parallel to and not normal to the laminations and theinterfaces between the laminations offer effective barriers to the flowof heat normal to the plane of the laminations. The sheet of asbestos i5interposed between the laminations I6 and the block of elastomer ifiserves to further protect the elastomer id from the heat of the weld. Itis not essential that this layer be asbestos. Any available rugged,flexible, heat resistant and insulating material may be used. In manyinmits, movable part I3 may in fact be xed and suilcient clearance forinsertion and withdrawal,

of sheet metal parts I may be obtained by relaxing the hydraulicpressurein: cavity I1.. When the sheet metal parts I0 arefin place, theymay be securely clamped by the provision of' adequate hydraulic pressurein cavity I1.

The apparatus shown in Figure. 3 is similar to.

that shown in Figure 1 except that asbestos strip I5 has been omittedand coolant tubes Il have been added to keep the temperature ofelastomer block` I4 within saie; operatinglimits.`

The apparatus. shownin. Figure 4 accomplishes the` necessary heatdissipation in a somewhat moredirectmanner.. Lamination I8 andlaminationA I il:l are Welded` together atv the. edges to I form aconduit. This conduit is connected to a. source ot Waterv under pressureandwhen the xture is not iniusefthe waterpressureforcesapart-,laminations I8. and I9'as shown in Figure 4 andpermits thewater: to flow through the conduit so formed. When thextureis in use the pressurefwill ilatte'nf this .conduit andy force.` out thewater.

Under. some-circumstances a single; lamination may be employed betweenthe workl and theasbestosoriy a plurality may be employed.` Itisimpe'rative` however that they laminations be few enough in number andthinenoughso that they can bedeformed. toaccommodate differences inthickness between the two sheets of metal to be joined and still applyadequate clamping pressure to each. Similarly these laminations must beflexible enough to compensate for wear or irregularities in the die II.Two laminations each about sixty thousandths of an inch thick have beenfoundto give satisfactory results.

It is to be understood that if desired, the die I I may be made movableand the opposing member xed or both may be made movable. SimilarlyVacoolant may be circulated through cavity I'T to dissipate any heatwhich may accumulate in the elastomer;

We. claim; as; our invention:

Inan apparatus for electrically welding sheet metal parts in edge toedge relationship, a pair of opposedclampng members, one of which isprovided with a groove for the reception of a welding electrode, theother of said clamping members comprising a block of elastomer uponwhich. is supported at least two. laminationsv of highly heat conductivemetal,.two edgeslof. said.

laminations being joined together. to form-.a coo1- ing conduit.

JOHN F..RA,NDALL. RICHARD E; BROOKS..

REFERENCES CITED.

The following references are of record in'. the

le of this patent:

UNITED STATES PATENTSv Number Name Date 1,612,317' Reed Dec. 28', 19261,640,437 Chapman Aug. 30,1927 1,840,737 Peck Jan. 12,1932 2,176,664Burke .Oct. 17;.1939 2,493,950 Dow et a1 Jan. 10, 1950

